36 JOURNAL OF CONCHOLOGY, VOL. l6, NO. I, JANUARY, I9I9. 



siderable distance along the Downs. If the species had been restricted 

 exclusively to Ditcham Woods, then the theory of foreign introduc- 

 tion might have been accepted, as Ditcham House is situated in the 

 centre of the woods, on the ridge of the Downs. But the snails are 

 found miles away, both east and west from this central wood, and in 

 my opinion are truly indigenous. 



It was recorded many years ago by Mr. Tomlin from Crabbe 

 Wood, near Winchester. This wood is situated on the north-western 

 extremity of the South Downs, twenty miles from Ditcham Wood. 

 This is the farthest point westward to which the species has been 

 traced. Eastward it occurs as far as Storrington in Sussex, fifteen 

 miles from Ditcham along the same chalk range, and as far as I am 

 able to judge, it is strictly confined to the chalk formation. 



This localised snail I feel convinced is a remnant of the ancient 

 continental fauna, which had managed to establish itself as far north 

 as the South Downs and possibly the North Downs before our islands 

 became finally separated from Europe. It is more than likely that 

 it spread across the great chalk hills which then connected Hampshire 

 and Sussex with the chalk ranges of France, and became isolated and 

 Confined to the present South Downs by the denudation of the chalk 

 ridges which then covered the Weald. The species had probably not 

 extended eastward into Kent before isolation occurred, while it had 

 not extended its range westward beyond Crabbe Wood. Between 

 Stoner Hill, a mile or so north-west of Petersfield, and Crabbe Wood 

 the species has apparently disappeared. There was a time probably 

 when it existed the whole length of the range of hills from Storrington 

 and in all probability even further to the east, to beyond Winchester, 

 but the destruction of the great woods which once clothed the Downs 

 has been the means of extirpating the species. Of course it is just 

 possible that it still exists in isolated patches of beech woodland, but 

 there are- few suitable woods of large extent remaining between Stoner 

 Hill and Crabbe Wood, and these are mostly plantations of compara- 

 tively recent growth. It is quite possible that as the older woods 

 disappear and are replaced by plantations of oak, fir, or other timber 

 the species will eventually die out. There are one or two places 

 where twenty years ago' I obtained living specimens, but where now 

 not even a dead shell can be found. I am strongly of opinion that 

 the species is a decadent one. 



{To be concluded^. 



